Benefits of Vitamin D, Sources and Deficiency
By: Tom alter
Vitamin D or calciferol, is a fat-soluble vitamin. It is mostly made in the human body after exposure to ultraviolet rays from the sun. The liver and kidney help convert vitamin D to its active hormone form.
Benefits of Vitamin D?
« Vitamin D aids in the absorption of calcium, helping to form and maintain strong bones. Vitamin D deficiency can make bones thin, brittle, soft and easily prone to fractures. Without sufficient vitamin D, our body cannot absorb calcium, rendering calcium supplements useless.
« Vitamin D acts like a hormone, thus regulating the absorption of calcium and phosphorus from the intestine.
« It helps to control the movement of calcium between bone and blood, and vice versa.
« It helps bone mineralization along with a number of other vitamins, minerals, and hormones of the body.
« Vitamin D prevents osteoporosis, depression, prostate cancer, breast cancer, and even helps control diabetes and obesity.
What are the sources of Vitamin D?
Food sources –
Only a few foods naturally contain significant amounts of vitamin D. Foods with naturally occurring vitamin D are usually animal derived containing the vitamin D3 (cholecalciferol). They include egg yolk, liver, fatty fish and fish oils. Smaller amounts are also present in dark leafy vegetables.
Fortified foods are the major dietary sources of vitamin D. Although milk, soya milk is fortified with vitamin D, dairy products made from milk such as curd, cheese, yogurt are usually not fortified.
It is important for individuals with limited sun exposure to include rich sources of vitamin D in their diet.
Exposure to sunlight –
Exposure to sunlight is an important source of vitamin D as ultraviolet (UV) rays from sunlight trigger vitamin D synthesis in the skin.
It is nearly impossible to get adequate amounts of vitamin D from diet. Sunlight exposure is the only reliable way to generate vitamin D in the body.
What can Vitamin D deficiency lead to?
« Vitamin D deficiency leads to rickets in children which results in skeletal deformities. In adults, vitamin D deficiency can lead to osteomalacia, which results in muscular weakness in addition to weak bones.
« Osteoporosis is commonly caused by a lack of vitamin D, which resists calcium absorption.
« Insufficient vitamin D leads to prostate cancer, ovarian cancer, colon cancer.
« Vitamin D deficiency may also make a person prone to Type 2 diabetes and impair insulin production. Infants who receive vitamin D supplementation have around 80% reduced risk of developing type 1 diabetes over the next twenty years.
« Vitamin D deficiency causes schizophrenia.
How much vitamin D is required?
The Food and Nutrition Board of the Institute of Medicine considers an intake of 1,000 IU for infants up to 12 months of age and 2,000 IU for children, adults, pregnant, and lactating women to be the tolerable upper intake level.
Daily intake above this level increases the risk of toxicity and is not advised.
Who all are at risk of Vitamin D deficiency?
« Older people as the ability of the skin to convert vitamin D to its active hormonal form decreases
with age. The kidneys, which help convert vitamin D, do not work quite well when people age.
« People who do not get adequate exposure to sunlight, such as women who cover their body outside for religious or cultural reasons or individuals working in occupations that prevent exposure to sunlight.
« People with dark skin synthesize less vitamin D on exposure to sunlight than those with light skin.
« Obesity increases the risk of vitamin D deficiency. Once vitamin D is synthesized in the skin, it is deposited in the body fat, making it less bio-available to overweight and obese people..
« Individuals who have reduced ability to absorb dietary fat as Vitamin D is a fat-soluble vitamin. This may be due to conditions such as pancreatic enzyme deficiency, Crohn's disease, bowel disease.
« Exclusively breast-fed infants because human milk may not contain adequate vitamin D.
Is too much of vitamin D risky?
Intake of too much vitamin D can cause toxicity leading to nausea, vomiting, poor appetite, constipation, weakness, and weight loss. It can also raise levels of calcium, causing mental status changes.
Calcinosis, the deposition of calcium and phosphate in soft tissues such as kidneys, lungs, blood vessels and heart can be caused by vitamin D toxicity. The kidneys may be permanently damaged and start malfunctioning.
A word of caution:
Even weak sunscreens (SPF of 8) block the body's ability to generate vitamin D by 95%. This is how sunscreen products actually cause disease by creating a critical vitamin deficiency in the body. Chronic Vitamin D deficiency cannot be reversed overnight: it takes months of vitamin D supplementation and sunlight exposure to rebuild the body's bones and nervous system.
Read more on benefits of vitamin d, food sources of vitamin d and deficiency.
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